1. Field of the Invention
The present invention relates to blinds and in particular to Venetian blinds for use primarily at windows but also suitable for use with glazed doors and other like locations. The invention also relates to components used in the manufacture of such blinds and to methods of manufacture or assembly of such blinds.
2. Description of the Relevant Art
Venetian blinds, which are also known as slatted blinds, are well known and conventionally comprise an upper supporting structure in the form of a head rail from which depend two or more spaced apart ladders. The ladders comprise a pair of longitudinal cords or threads aligned in use substantially parallel to the window with a plurality of lateral threads inter-connecting the longitudinal cords at regular intervals. The lateral threads support respective laths or slats which form the shading part of the blind. The slats may rest on the lateral threads without any attachment, or some or all of the slats may be directly connected to respective lateral threads.
Mechanisms are conventionally provided by which the blind can be raised and lowered so that it can adopt configurations in which the window is wholly shaded, partially shaded or unshaded. Such mechanisms will normally include at least one lift cord which may pass through holes defined in the slats of the blind. Also, mechanisms are provided by which the slats can be tilted or inclined out of a nominally horizontal alignment into alignments tending towards the vertical, thereby to vary the degree of shading provided by the blind. Tilting is conventionally effected by adjusting the configurations of the longitudinal cords of the ladders. Examples of such mechanisms known from the prior art include the following:
EP 0 976 908 teaches a relatively simple arrangement in which two ladders are provided. The longitudinal cords of the ladders pass through respective apertures in the underside of a control box or head rail. The cords are separated on passing through the aperture and secured at spaced apart locations to a control cable. Movement of the control cable in one direction thus causes one cord of a given ladder to be raised while the other is lowered and movement of the control cable in the other direction has the equivalent effect in the opposite sense.
DE 33 13 833 describes an essentially similar arrangement in which a control rod has fixedly mounted thereon cord attachment brackets. The control rod is connected to a rack and worm drive arrangement by which it can be moved laterally, having the same effect on the ladder cords as in EP 0 976 908.
SE 457 978 teaches that the respective ladder cords are attached to opposed sides of slidable plates mounted in a head rail. The plates are caused to slide by means of a user-operated control cord.
U.S. Pat. No. 5,934,351 teaches a blind having a pair of linked sliders arranged to slide along the bottom wall of the head rail. The respective cords of the ladders pass through apertures in the bottom wall and through apertures in the sliders. The individual cords are attached to opposed ends of the sliders. Movement of the sliders under the action of a user operated control cord thus causes tilting of the slats of the blind.
EP 1 431 507 teaches a Venetian blind including a head rail mounted control arrangement. The head rail includes apertures arranged in register with the ladder cords, and bearing blocks mounted at the apertures. A control bar is slidably mounted on the bearing blocks. The control bar has fastening elements attached towards its ends to opposed ends of which respective ends the ladder cords are attached. The control bar is attached to a rack and pinion arrangement which is in turn moveable by a user operated control wand.